Driving assistance device

ABSTRACT

A driving assistance device performs collision avoidance control for avoidance of a collision between a vehicle and an object being around the vehicle and detected by an object detector, the collision avoidance control being performed based on collision determination as to a collision between the object and the vehicle. The driving assistance device includes: an object sensing section that senses an object around the vehicle; a blind spot area setting section that sets a blind spot area at an area positioned in the vehicle&#39;s blind spot blocked by an obstacle sensed by the object sensing section; an early determination area setting section that sets an early determination area including the blind spot area and extended therefrom; and a collision determination section that accelerates the collision determination for an object sensed in the early determination area, compared with the collision determination for an object sensed outside the early determination area.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims the benefit of priorityfrom earlier Japanese Patent Application No. 2019-023030 filed on Feb.12, 2019, the description of which is incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to a driving assistance device thatperforms collision avoidance control for avoidance of a collisionbetween an own vehicle and an object around the own vehicle.

Related Art

A driving assistance device is known which performs braking or othercollision avoidance control when an own vehicle and an object around theown vehicle are determined to be likely to collide with each other.

SUMMARY

As an aspect of the present disclosure, a driving assistance device forperforming collision avoidance control for avoidance of a collisionbetween an own vehicle and an object being around the own vehicle anddetected by an object detector is provided. The collision avoidancecontrol is performed based on collision determination as to a collisionbetween the own vehicle and the object. The driving assistance deviceincludes: an object sensing section configured to sense an object aroundthe own vehicle; a blind spot area setting section configured to set ablind spot area at an area positioned in an own vehicle's blind spotblocked by an obstacle, which is a moving body, sensed by the objectsensing section; an early determination area setting section configuredto set an early determination area including the blind spot area andextended from the blind spot area along a path of the obstacle estimatedbased on a traveling direction of the obstacle or a traveling state ofthe obstacle; and a collision determination section configured toaccelerate the collision determination for an object sensed in the earlydetermination area, compared with the collision determination for anobject sensed outside the early determination area.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a block diagram illustrating a driving assistance systemincluding a driving assistance device according to a first embodiment;

FIG. 2 illustrates blind spot areas and early determination areas;

FIG. 3 illustrates a blind spot area and an early determination area;

FIG. 4 illustrates determination of a possibility of presence in a blindspot area;

FIG. 5 illustrates a blind spot area and an early determination area atan intersection;

FIG. 6 illustrates a blind spot area and an early determination area atan intersection;

FIG. 7 is a flowchart of driving assistance control according to thefirst embodiment;

FIG. 8 is a flowchart of a blind spot area setting process;

FIG. 9 is a flowchart of an early determination area setting process;and

FIG. 10 is a flowchart of driving assistance control according to asecond embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A driving assistance device is known which performs braking or othercollision avoidance control when an own vehicle and an object around theown vehicle are determined to be likely to collide with each other.Appropriate avoidance of a collision with a moving body emerging from ablind spot of the own vehicle needs quick completion of the process forsensing the moving body emerging from the blind spot of the own vehicle,performing collision determination as to whether the sensed moving bodywill collide with the own vehicle, and performing collision avoidancecontrol. JP 2015-82157 A describes a technique in which a possiblemoving body within a blind spot area is set as a virtual target, and ifthe virtual target is likely to collide with the own vehicle, a sensornarrows its object sensing range in the vicinity of the boundary of theblind spot area from which the virtual target would emerge. The sensorsenses the moving body earlier to achieve early detection of thesituation in which the virtual target emerges from the blind spot.

JP 2015-82157 A discloses a technique for accelerating object sensing bya sensor, not a technique for accelerating collision determination as toa sensed object.

In view of the above, an object of the present disclosure is to providea technique for accelerating collision determination between an ownvehicle and an object appearing from its blind spot area.

First Embodiment

As shown in FIG. 1, a driving assistance system 10 according to theembodiment includes a radar 21, an imager 22, a vehicle speed sensor 23,a steering angle sensor 24, a yaw rate sensor 25, a receiver 26, an ECU30, and a controlled device 40. The controlled device 40 includes analarm 41 and a brake 42. The driving assistance system 10 isincorporated in an own vehicle and functions as a pre-crash safety (PCS)system that performs control to avoid a collision between the ownvehicle and an object determined to collide with the own vehicle orreduce collision damage to the own vehicle.

The radar 21 is, for example, a known millimeter-wave radar that uses ahigh frequency signal within a millimeter-wave band as a transmissionwave. The own vehicle may have a single radar 21 or a plurality ofradars 21. The radar 21 is mounted, for example, on the front end or thelike of the own vehicle. The radar 21 defines an area within apredetermined sensing angle as a sensing range in which an object can besensed, and locates an object within the sensing range. Specifically,the radar 21 transmits a probe wave periodically and receives reflectedwaves through a plurality of antennas. The transmission time of a probewave and the reception time of a reflected wave can be used to calculatea distance from an object. Furthermore, the change in frequency of areflected wave from an object due to the Doppler effect can be used tocalculate a relative velocity. In addition, a phase difference betweenreflected waves received through the plurality of antennas can be usedto calculate the direction to the object. If the position and thedirection of the object are calculated, a relative position of theobject to the own vehicle can be determined.

The imager 22 may be a monocular camera such as a CCD camera, a CMOSimage sensor, or a near-infrared camera or may be a stereo camera. Theown vehicle may have a single imager 22 or a plurality of imagers 22.The imager 22 is mounted, for example, at a predetermined height in thewidth-directional center of the vehicle, and from above, images an areaspreading at a predetermined angle forward or rearward from the vehicle.The imager 22 extracts feature points indicating the presence of anobject in the captured image. Specifically, the imager 22 extracts edgepoints based on the luminance information about the captured image, andperforms the Hough transform on the extracted edge points. For example,the Hough transform extracts, as feature points, points on a straightline having consecutive edge points and the intersections of orthogonalstraight lines. The imager 22 outputs successively captured images tothe ECU 30 one after another as sensing information.

The radar 21 and the imager 22 are example object sensing devices thatacquire the environmental information about the own vehicle. Otherexamples of object sensing devices include sensors that send a probewave such as an ultrasound sensor and LIDAR (light detection andranging/laser imaging detection and ranging). A millimeter-wave radarsuch as the radar 21 or a sensor that sends a probe wave such as a lasersensor, sonar, or LIDAR receives a reflected wave from an obstacle toobtain a reception signal, and outputs scanning results that are basedon the reception signal to the ECU 30 one after another as sensinginformation.

The above various object sensing devices may sense not only a forward ora side object from the own vehicle but also a rearward object and usethe sensing results as positional information. The target object to bemonitored may also be changed in accordance with the type of the objectsensing device to be used. For example, when the imager 22 is used,target objects are preferably stationary objects such as road signs andbuildings. When the radar 21 is used, target objects are preferablyobjects that reflect at high electrical power. The object sensing deviceto be used may be selected in accordance with the types, the positions,and the moving speeds of target objects.

The speed sensor 23 is a sensor that senses a traveling speed of the ownvehicle such as, but not limited to, a wheel speed sensor capable ofsensing a wheel rotational speed. The wheel speed sensor used as thespeed sensor 23 is mounted, for example, on a wheel portion, and outputsa wheel speed signal in accordance with the vehicle wheel speed to theECU 30.

The steering angle sensor 24 is mounted, for example, on the vehiclesteering rod, and outputs a steering angle signal in accordance with thechange in the steering angle of the steering wheel due to the driver'soperation to the ECU 30.

The own vehicle may have a single yaw rate sensor 25 or a plurality ofyaw rate sensors 25. With only one yaw rate sensor 25, it will beinstalled, for example, at the center of the own vehicle. The yaw ratesensor 25 outputs a yaw rate signal in accordance with the rate ofchange in the steering quantity of the own vehicle to the ECU 30. With aplurality of yaw rate sensors 25, the average or the median of theirsensed values may be used. In calculating the average of a plurality ofsensed yaw rates, the sensed values may be weighted.

The receiver 26 is a GPS receiver, which is one example globalnavigation satellite system (GNSS) receiver. The receiver 26 can receivepositioning signals from a satellite positioning system that usesartificial satellites to determine the current ground position.

The ECU 30 functions as a driving assistance device that performsdriving assistance for the own vehicle by producing a control commandbased on information obtained from the radar 21, the imager 22, thevehicle speed sensor 23, the steering angle sensor 24, the yaw ratesensor 25, and the receiver 26 and outputting the produced controlcommand to the controlled device 40.

The controlled device 40 may be configured to operate based on thecontrol command from the ECU 30 as well as operate in accordance withthe driver's operation input. The driver's operation may be subjected toappropriate processing by the ECU 30 before being input to thecontrolled device 40 as a control command from the ECU 30.

The alarm 41 is a device for notifying the driver and other passengers,such as, but not limited to, a speaker, a buzzer, or other auditorynotification device installed in the own vehicle, or a display or othervisual notification device. The alarm 41 emits an alarm sound based on acontrol command from the ECU 30 to, for example, notify the driver of apossible danger of a collision with an object.

The brake 42 is a device for braking the own vehicle and controlled bydriver's braking operation or a command from the ECU 30. The ECU 30 mayhave a brake assist function that increases braking force of thedriver's braking operation and an automatic brake function thatactivates automatic braking without the driver's braking operation, asbrake functions for avoidance of a collision with an object or reductionin collision damage. The brake 42 allows brake control by thesefunctions based on a control command from the ECU 30.

The controlled device 40 may also include a steering unit for steeringthe own vehicle and a drive unit including a vehicle driving source suchas an internal combustion engine, a motor, and a storage battery.

The ECU 30 includes a data acquisition section 31, an object sensingsection 32, a blind spot area setting section 33, an early determinationarea setting section 34, a collision determination section 35, and adriving assistance section 36. The ECU 30 includes a CPU, ROM, RAM, andan I/O unit, and the CPU executes programs installed in the ROM toimplement the functions of the above sections.

The data acquisition section 31 acquires sensing data obtained by theradar 21, the imager 22, and the sensors 23 to 25 and positioningsignals received by the receiver 26. Various kinds of data acquired bythe data acquisition section 31 and values calculated based on thevarious kinds of data may also be stored in the ECU 30.

The object sensing section 32 can sense an object around the own vehiclebased on sensing data obtained from the object sensing devices such asthe radar 21 and the imager 22. For example, as shown in FIG. 2, theobject sensing section 32 of an own vehicle 50 can sense another vehicle51 being in the traveling direction (ahead) of the own vehicle 50. It ispreferable that the object sensing section 32 be configured to identifysensed objects. For example, it is preferable that the object sensingsection 32 be configured to identify a sensed object as a car, abicycle, a motorcycle, a person, an animal, or a stationary groundobject such as a guardrail.

The blind spot area setting section 33 sets a blind spot area at an areablocked by an obstacle sensed by the object sensing section 32, that is,an area positioned in a blind spot of the own vehicle. Note that anobstacle refers to an object sensed by the object sensing section 32 andblocking the object sensing devices such as the radar 21 and the imager22 from sensing. The blind spot of the own vehicle disables the objectsensing devices for sensing. The obstacle may be a moving body or astationary body. It is preferable that the blind spot area settingsection 33 be configured to determine, for every object sensed by theobject sensing devices, whether the object produces a blind spot for theown vehicle, and for every object determined to produce a blind spot,set a blind spot area with the object treated as an obstacle.

The blind spot area setting section 33 determines whether the objectsensing devices such as the radar 21 and the imager 22 have a blind spot(an area that cannot be sensed by the object sensing devices), and setsa blind spot area when there is a blind spot. The blind spot areasetting section 33 may set the entire blind spot as a blind spot area,or a part of the blind spot as a blind spot area. For example, based onthe orientation and the traveling direction of an obstacle, the blindspot area setting section 33 may set, as a blind spot area, a partialarea estimated to be highly likely to need accelerated collisiondetermination as to a moving body emerging from the area.

The blind spot area setting section 33 may be configured to set a blindspot area beyond an obstacle from the own vehicle. The further area ofan obstacle from the own vehicle corresponds to an area positioned inthe blind spot of the own vehicle.

The blind spot area setting section 33 may be configured to set a blindspot area based on the angle formed by the own vehicle and sensingpoints indicating the outer edge of an obstacle. Based on the angleformed by the own vehicle and the sensing points indicating the outeredge of the obstacle, the blind spot area setting section 33 may set anedge line from the own vehicle position to each sensing point and definethe area within the edge lines as a blind spot area.

For example, as shown in FIG. 2(a), the other vehicle 51 sensed ahead ofthe own vehicle 50, almost facing the own vehicle 50, and moving nearerto the own vehicle 50 is determined as an obstacle. The angle formed bythe own vehicle 50 and sensing points 51R and 51L indicating the outeredge of the other vehicle 51, which is an obstacle, is calculated. Thesensing point 51L is the leftmost sensing point of the other vehicle 51as viewed from the own vehicle 50, whereas the sensing point 51R is therightmost sensing point of the other vehicle 51 as viewed from the ownvehicle 50. The angle calculated from the sensing point 51L is used toset a leftmost line 50L, and the angle calculated from the sensing point51R is used to set a rightmost line 50R. The leftmost line 50L is anedge line extending substantially through the sensing point 51L, whereasthe rightmost line 50R is an edge line extending substantially throughthe sensing point 51R.

Of the area defined between the leftmost line 50L and the rightmost line50R in this case, the further area of the other vehicle 51 from the ownvehicle 50 (specifically, the areas denoted by reference numerals 60 and61) is an area positioned in the blind spot of the own vehicle. In anexample, when the areas 60 and 61 beyond the other vehicle 51 from theown vehicle 50 are set as a blind spot area, the entire area positionedin the blind spot of the own vehicle 50 is defined as the blind spotarea.

The sensing points indicating the outer edge of the other vehicle 51,which is an obstacle, are not limited to the leftmost sensing point 51Land the rightmost sensing point 51R, and other sensing points on theouter edge of the other vehicle 51 may also be used. The number ofsensing points may be two or more and is not limited to a particularnumber. However, four or more sensing points are preferably used. It isfurther preferable to use sensing points positioned substantially at theright end and the left end on the outer edge of the other vehicle 51.

The blind spot area setting section 33 may set a part of the areapositioned in the blind spot of the own vehicle as a blind spot area.For example, the blind spot area setting section 33 may set a blind spotarea defined by a line substantially parallel to the orientation or thetraveling direction of the obstacle.

Specifically, as shown in FIG. 2(a), the orientation (forward direction)and the traveling direction of the other vehicle 51, which is anobstacle, correspond to the negative Y-direction. In this case, for thearea positioned in the blind spot of the own vehicle (the area includingboth the areas 60 and 61), the blind spot area setting section 33 may beconfigured to set, as a blind spot area 60, the further area (thepositive X-directional area in FIG. 2(a)) defined by a line 60Lsubstantially parallel to the orientation and the traveling direction ofthe other vehicle 51 (i.e., the negative Y-direction). Since the area 61is positioned behind the other vehicle 51, an object emerging from thearea 61 is likely to appear at the nearer side of the other vehicle 51.Thus, a collision is likely to be avoided without accelerating thecollision determination. By excluding the area 61 from the blind spotarea, the area 60, which is estimated to be highly likely to needaccelerated collision determination, is defined as a blind spot area.

Similarly, in an example as shown in FIG. 3, another vehicle 53 sensedahead of the own vehicle 50 and passing in front of the own vehicle 50in the negative X-direction is determined as an obstacle. Theorientation (forward direction) and the traveling direction of the othervehicle 53, which is an obstacle, correspond to the negativeX-direction. In this case, for the area positioned in the blind spot ofthe own vehicle 50, the blind spot area setting section 33 may beconfigured to set, as a blind spot area 63, the further (the positiveY-directional) area defined by a line 63N substantially parallel to theorientation and the traveling direction of the other vehicle 53 (i.e.,the negative X-direction).

The blind spot area setting section 33 may be configured to set a blindspot area beyond the opposite side (further side) of the obstacle fromthe own vehicle. For example, the object sensing section 32 maydetermine the type of the obstacle to estimate the shape of theobstacle, enabling the position of the further side of the obstacle tobe estimated. Specifically, for the other vehicle 51 shown in FIG. 2(a),the blind spot area setting section 33 may be configured to set the areabeyond the positive X-directional side opposite from the own vehicle 50(i.e., the positive X-directional area) as the blind spot area 60.

The early determination area setting section 34 sets an earlydetermination area (priority determination/detection area) including ablind spot area and extended from the blind spot area. The earlydetermination area is an area for which the collision determinationsection 35 described later is quick to make (accelerates) collisiondetermination.

In one example, an area 70 obtained by extending the blind spot area 60in FIG. 2(a) by an extension area 70E is set as an early determinationarea. The early determination area 70 is an area enclosed by the linedenoted by reference numeral 70 in FIG. 2, and includes the blind spotarea 60 and the extension area 70E. In another example, an area 73obtained by extending the blind spot area 63 in FIG. 3 by an extensionarea 73E is set as an early determination area.

The early determination area 73 is an area enclosed by the line denotedby reference numeral 73 in FIG. 3, and includes the blind spot area 63and the extension area 73E.

The early determination area setting section 34 may determine whether toset an early determination area by using information acquired from theimager 22 about a road surface marking or a road sign around the ownvehicle, and own vehicle positional information, geographic information,and traffic information acquired from the receiver 26, and may alsodetermine the direction and the amount of the extension of the earlydetermination area.

The early determination area setting section 34 may set an earlydetermination area for every object around the own vehicle or may beconfigured to set an early determination area simply for an objectsensed in the traveling direction of the own vehicle.

In one example, the early determination area setting section 34 may beconfigured to set an early determination area for the blind spot areadue to an obstacle sensed in the traveling direction of the own vehicle.

In another example, the early determination area setting section 34 maybe configured to set an early determination area when the own vehiclepath estimated based on the current traveling state of the pen vehiclecrosses the obstacle path estimated based on the current traveling stateof an obstacle.

FIG. 2(c) illustrates an estimated path 50P of the own vehicle 50 and anestimated path 51P of the other vehicle 51, which is an obstacle, withthe own vehicle 50 and the other vehicle 51 having the same positionsand traveling states as shown in FIG. 2(a). As shown in FIG. 2(c), theearly determination area setting section 34 sets an early determinationarea 71 when the path 50P of the own vehicle 50 and the path 51P of theother vehicle 51 cross each other.

In one example, the early determination area setting section 34 may beconfigured to set an early determination area when the own vehicle andan obstacle are close to each other. More specifically, for example,when the distance between the own vehicle and an obstacle is equal to orless than a predetermined distance threshold, an early determinationarea may be set. The distance between the own vehicle and an obstaclemay be divided into the distance in the traveling direction of the ownvehicle and the lateral distance substantially vertical to the travelingdirection of the own vehicle, and each distance may be evaluated.

In another example, the early determination area setting section 34 maybe configured to set an early determination area when the own vehiclepath estimated based on the current traveling state of the own vehicleruns near an obstacle. As shown in FIG. 2(c), the early determinationarea setting section 34 sets the early determination area 71 when thepath 50P of the own vehicle 50 runs near the other vehicle 51.

The early determination area setting section 34 may be configured todetermine the possibility of the blind spot area including space for anyobject other than the obstacle (possibility of presence). Based on thedetermination result of the possibility of presence, the earlydetermination area setting section 34 may be configured to determinewhether to set an early determination area. For example, if thedetermination result of the possibility of presence is affirmative, thatis, the blind spot area is determined to include space for any objectother than the obstacle, then an early determination area may be set.

In one example as shown in FIG. 2(a), object sensing around the ownvehicle by the object sensing devices may suggest the possibility of theblind spot area 60 including enough space. In this case, the blind spotarea 60 can be determined to include space for any other moving bodysuch as another vehicle 52. In another example, acquired roadinformation around the own vehicle may indicate that the number ofoncoming lanes next to the own vehicle is two or more. In this case,when the other vehicle, which is an obstacle, is found to run in theoncoming lane other than the furthest lane from the own vehicle, theblind spot area can be determined to include space for any other movingbody. In yet another example, when the distance between the othervehicle, which is an obstacle, and the road edge of the traffic lane inwhich the other vehicle runs is equal to or more than a predeterminedroad edge distance threshold, the blind spot area is estimated toinclude enough space, and the blind spot area can be determined toinclude space for any other moving body.

In another example as shown in FIG. 4, when another vehicle 54, which isan obstacle, is traveling just along a road edge 80, the other vehicle54 and the road edge 80 have little space between them. In this case, ablind spot area 64 set for the other vehicle 54 can be estimated toinclude not enough space. Thus, the blind spot area 64 can be determinedto include no space for any other moving body.

Even when determining the possibility of presence, the earlydetermination area setting section 34 may be configured to set an earlydetermination area irrespective of the determination result of thepossibility of presence if a predetermined cancellation condition issatisfied. Note that a cancellation condition refers to a condition forcanceling the determination of the possibility of presence.

For example, the own vehicle entering an intersection may be acancellation condition. Note that an intersection refers to acrossroads, a T-junction, or other section where two or more roads (orroadways for roads in which sidewalks and roadways are distinct) crosseach other.

FIG. 5 illustrates an intersection (crossroads) where a road 81extending in the Y-direction and a road 82 extending in the X-directioncross each other. In FIG. 5, the own vehicle 50 traveling on the road 81enters the intersection, while another vehicle 55 traveling in theoncoming lane of the road 81 enters the intersection. In FIG. 5, the ownvehicle 50 is turning right from the road 81 to the road 82, while theother vehicle 55 is turning left from the road 81 to the road 82.

As shown in FIG. 5, the other vehicle 55, which is an obstacle, and thecorner of the crossroads have a small distance between them. Thus, inthe determination of the possibility of presence, the distance betweenthe other vehicle 55 and the road edge may be determined to be less thanthe predetermined road edge distance threshold, and a blind spot area 65may be determined to include no space for any moving body different fromthe other vehicle 55.

However, there may be a pedestrian 56 who is about to cross the road 82at a crosswalk 83 from the sidewalk outside the road. In this case, thepedestrian 56 will move toward the path 50P of the own vehicle 50, andthe pedestrian 56 and the own vehicle 50 may collide with each other.Such a collision with the pedestrian 56 can easily be avoided bydefining the own vehicle 50 entering an intersection as a cancellationcondition. In other words, when the own vehicle 50 moves toward anintersection, an early determination area 75 is set irrespective of thedetermination result of the possibility of presence to facilitateavoidance.

The early determination area setting section 34 may be configured toset, as an early determination area, an area obtained by extending ablind spot area along the orientation or the traveling direction of theobstacle. For example, as shown in FIG. 2(a), the early determinationarea setting section 34 may set the early determination area 70 obtainedby extending the blind spot area 60 in the negative Y-direction alongthe orientation and the traveling direction of the other vehicle 51,which is an obstacle (i.e., the negative Y-direction).

When the traveling direction of an obstacle is the same as that of theown vehicle 50, that is, as shown in FIG. 2(b), when another vehicle 51Bthat is an obstacle is traveling in the same direction as the ownvehicle 50, the early determination area setting section 34 may set anearly determination area 77 obtained by extending the blind spot area 60in the positive Y-direction along the traveling direction of the othervehicle 51B (i.e., the positive Y-direction). Note that the othervehicle 51B is a vehicle traveling and facing in the direction oppositeto the other vehicle 51 in FIG. 2(a), and the other vehicle 51B and theother vehicle 51 are at the same position relative to the own vehicle50.

In another example as shown in FIG. 3, the early determination areasetting section 34 may set the early determination area 73 obtained byextending the blind spot area 63 in the negative X-direction along theorientation and the traveling direction of the other vehicle 53, whichis an obstacle (i.e., the negative X-direction).

The early determination area setting section 34 may be configured toset, as an early determination area, an area obtained by extending theblind spot area toward the position at which the own vehicle pathestimated based on the traveling state of the own vehicle and theobstacle path estimated based on the traveling state of the obstaclecross each other. FIG. 2(c) illustrates the path 50P of the own vehicle50 and the path 51P of the other vehicle 51, which is an obstacle, withthe own vehicle 50 and the other vehicle 51 having the same positionsand traveling states as shown in FIG. 2(a). As shown in FIG. 2(c), anextension area 71E is set for the blind spot area 60 toward the positionat which the path 50P and the path 51P cross each other, that is, in thenegative Y-direction. Then, the early determination area 71 is setincluding the blind spot area 60 and the extension area 71E.

The early determination area setting section 34 may be configured toset, as an early determination area, an area obtained by extending theblind spot area toward the own vehicle path estimated based on thetraveling state of the own vehicle. FIG. 2(d) illustrates the path 50Pof the own vehicle 50 with the own vehicle 50 and the other vehicle 51having the same positions and traveling states as shown in FIG. 2(a). Asshown in FIG. 2(d), an extension area 72E is set for the blind spot area60 toward the path 50P, that is, in the negative Y-direction. Then, anearly determination area 72 is set including the blind spot area 60 andthe extension area 72E.

As shown in FIGS. 2(a) to (d), the early determination area settingsection 34 can set an early determination area extended simply in thetraveling direction of an obstacle, in which the possibility of acollision with the own vehicle is high, thus reducing the computationalload in the collision determination within the early determination areato accelerate the collision determination further. However, the earlydetermination area setting section 34 may also be configured to set anearly determination area extended away from the traveling direction ofthe obstacle, or in the direction in which the possibility of acollision with the own vehicle is relatively low. In other words, inFIGS. 2(a) to (d), extension areas may also be provided both in thepositive and the negative Y-directions.

The early determination area setting section 34 may be configured todetermine the size of the early determination area. The size of theearly determination area varies with the size of the extension area.That is, the early determination area setting section 34 may beconfigured to determine the size of the extension area to determine thesize of the early determination area.

The extension area may be an area extended substantially evenly in eachdirection of extension. For example, in FIG. 2(a), the extension area70E may have a constant Y-directional size at any X-directionalposition.

In contrast, the extension area may vary in size depending on thedirection of extension. For example, in FIG. 2(a), the Y-directionalsize of the extension area 70E may vary with X-directional positions.More specifically, the Y-directional size of the extension area 70E mayincrease with decreasing X-directional distance to the own vehicle 50.In another example in which extension areas are set not only in thetraveling direction of the obstacle, but also in the direction oppositeto the traveling direction or other direction, the extension areaextending in the traveling direction of the obstacle, in which thepossibility of a collision with the own vehicle is higher, may be largerthan the extension area extended in the other direction. Specifically,in FIG. 2(a), an extension area may be set in a direction different fromthe negative Y-direction, which is the traveling direction of the othervehicle 51 (e.g., in the positive Y-direction). In this case, theextension area extended in the negative Y-direction may be larger thanthe extension area extended in the positive Y-direction. In FIG. 2(b),an extension area may be set in a direction different from the positiveY-direction, which is the traveling direction of the other vehicle 51B(e.g., in the negative Y-direction). In this case, the extension areaextended in the positive Y-direction may be larger than the extensionarea extended in the negative Y-direction.

The early determination area setting section 34 may determine the sizeof the extension area as a predetermined fixed value, and the fixedvalue may be stored in the ECU 30. The early determination area settingsection 34 may also be configured to determine the size of the extensionarea based on at least one of the velocity of the obstacle and therelative velocity of the obstacle to the own vehicle.

A specific example will now be described with reference to FIG. 2(a).For example, during the cyclic execution of driving assistance controlprocessing, the other vehicle 52 may suddenly emerge from the blind spotarea 60 and be sensed in the extension area 70E of the earlydetermination area 70. In this case, with increasing velocity of theother vehicle 51, which is an obstacle, the likelihood of the othervehicle 52 running far behind the other vehicle 51 increases in the nextprocessing cycle. Thus, it is preferable to enlarge the earlydetermination area in which collision determination processing isaccelerated, speeding up the processing per cycle. In other words, it ispreferable to enlarge the extension area 70E as the velocity of theother vehicle 51, which is an obstacle, increases.

Similarly, as shown in FIG. 2(b), when the other vehicle 51B, which isan obstacle, is traveling in the same direction as the own vehicle 50,it is preferable to enlarge an extension area 77E as the velocity of theother vehicle 51B, which is an obstacle, increases.

Also when the relative velocity of an obstacle to the own vehicle ishigh, it is preferable to enlarge the extension area. In other words, asthe relative velocity of the other vehicle 51 or 51B, which is anobstacle, to the own vehicle 50 increases, it is preferable to enlargethe extension area 70E or 77E.

The size of the early determination area (or the size of the extensionarea) may be stored in the ECU 30 as a numerical expression, a map, or adatabase indicating the relationship with a predetermined parameter suchas the relative velocity of an obstacle to the own vehicle. The earlydetermination area setting section 34 may acquire the predeterminedparameter to calculate the size of the early determination area basedon, for example, the numerical expression stored in the ECU 30.

The early determination area setting section 34 may be configured tochange the way of setting an early determination area based on theenvironmental road information. For example, as shown in FIG. 5, whenthe own vehicle 50 enters an intersection, the early determination areasetting section 34 may be configured to set an early determination areathat is the early determination area 75 including an extension area 75Eextending from the blind spot area 65 toward the own vehicle 50. Whenthe own vehicle 50 turns right at the intersection from the road 81 tothe road 82, a moving body passing straight across the intersectionalong the road 81 may emerge toward the own vehicle 50 from the blindspot area 65. A collision with such a moving body can easily be avoidedby setting the early determination area 75 extended toward the ownvehicle 50.

In another example as shown in FIG. 6, when the own vehicle 50 enters anintersection, the early determination area setting section 34 may beconfigured to set an early determination area 76 including an extensionarea 76E extending from a blind spot area 66 along the path 50P of theown vehicle 50 estimated based on the traveling state of the own vehicle50. In FIG. 6, the negative Y-directional end of the early determinationarea 76 is extended to the rightward path of the own vehicle 50 in thepath 50P. When the pedestrian 56 about to cross at the crosswalk 83suddenly emerges from the blind spot area 66, the above settingfacilitates avoidance of the danger of a collision with the own vehicle50.

In collision determination, the collision determination section 35 firstdetermines the presence or absence of the possibility that an objectaround the own vehicle may collide with the own vehicle (collisionpossibility). Then, for the object determined to have a collisionpossibility, the collision determination section 35 performs activationdetermination as to whether to activate the controlled device 40. Thecollision determination performed by the collision determination section35 includes the collision possibility determination and the activationdetermination.

Specifically, the collision determination section 35 uses the ownvehicle path estimated based on the traveling state of the own vehicleand the object path estimated based on the moving state of an objectaround the own vehicle to determine whether the object around the ownvehicle may collide with the own vehicle. For example, when the path ofthe own vehicle and the path of the object around the own vehicle are incontact or close to each other, the collision determination section 35determines the presence of a collision possibility between the ownvehicle and the object. In contrast, when the path of the own vehicleand the path of the object around the own vehicle are apart from eachother, the collision determination section 35 determines the absence ofa collision possibility. Note that the own vehicle path and the objectpath may be estimated by any method, such as a conventionally knownestimation method.

The collision determination section 35 further calculates the time tocollision (TTC) for the object determined to have a collisionpossibility. The time to collision is the time left until the ownvehicle and the object collide with each other, and can be calculatedbased on the relative distance between the own vehicle and the object.Then, the time to collision and the activation timing set for thecontrolled device 40 are compared to determine whether to activate thecontrolled device 40 for avoidance of the collision. Note that theactivation timing refers to the timing to activate the controlled device40. Different activation timings may also be set for the targets to beactivated (such as the alarm 41 and the brake 42).

The collision determination section 35 accelerates the collisiondetermination for an object sensed by the radar 21 or the imager 22within the early determination area, compared with the collisiondetermination for an object sensed outside the early determination area.Specifically, the collision determination section 35 determines whetherthe own vehicle will collide with an object detected within the earlydetermination area in a collision determination period shorter than foran object detected outside the early determination area. Note that thecollision determination period is the time taken to conclude thedetermination as to whether the object and the own vehicle will collidewith each other.

The collision determination section 35 may accelerate either one or bothof the collision possibility determination and the activationdetermination for an object sensed within the early determination area.The collision determination section 35 may be configured to acceleratethe collision determination evenly at any position within the earlydetermination area. In contrast, the collision determination section 35may also be configured to change the degree of acceleration of thecollision determination in accordance with the position within the earlydetermination area. For example, a position estimated to have a greatercollision possibility in the early determination area may be associatedwith a higher degree of (further) acceleration. Specifically, thecollision determination section 35 may be configured to accelerate thecollision determination further at a position closer to the own vehiclewithin the early determination area.

Specifically, for example, a shorter collision determination period isset by relaxing the conditions used for collision determination. Theconditions include the number of images (the number of frames) used todetermine the path of a moving object and the lateral movement distance(absolute value) of the moving object.

For a condition concerning the number of images, the relaxation of thecondition refers to reducing the number of images. For a conditionconcerning the movement distance, the relaxation of the condition refersto lowering the value of the distance. This enables the collisiondetermination between the object and the own vehicle to be concludedearlier. The degree of relaxation of the conditions can be changed tochange the degree of acceleration.

When the collision determination section 35 determines the controlleddevice 40 to be activated, the driving assistance section 36 issues acommand to the controlled device 40 to perform control associated withcollision avoidance such as notification or braking.

An example of the driving assistance control performed by the ECU 30according to the first embodiment will now be described with referenceto a flowchart shown in FIG. 7. The process shown in FIG. 7 is repeatedat fixed intervals during the operation of the own vehicle.

First, in step S101, an object around the own vehicle is sensed based ondata obtained from the radar 21 and the imager 22. For example, theradar 21 senses an object, and the imager 22 obtains sensing points ofthe object to acquire information about its size and shape.Additionally, the type of the sensed object (e.g., a vehicle, a bicycle,a motorcycle, a person, an animal, or a stationary ground object such asa guardrail) is estimated. Then, the processing proceeds to step S102.

In step S102, it is determined whether there is a blind spot area. Forexample, it is determined whether the object sensing devices such as theradar 21 and the imager 22 have a blind spot (an area that cannot besensed by the object sensing devices). If there is a blind spot, thepresence of a blind spot area is determined, and the processing proceedsto step S103. If there is no blind spot, the absence of a blind spotarea is determined, and the processing is ended.

In step S103, the blind spot area is set for the sensed obstacle. Anexample of the processing in step S103 is shown in FIG. 8.

In step S201 in FIG. 8, the position, the orientation, and the travelingdirection of the obstacle are obtained. Note that the position, theorientation, and the traveling direction of the obstacle can becalculated based on sensing information obtained from the radar 21 andthe imager 22.

Subsequently, in step S202, the position, the orientation, and thetraveling direction of the own vehicle are obtained. Then, theprocessing proceeds to step S203. The position, the orientation, and thetraveling direction of the own vehicle can be calculated based onsensing information obtained from the speed sensor 23, the steeringangle sensor 24, and the yaw rate sensor 25.

In step S203, the direction for setting the blind spot area iscalculated based on the information obtained in steps S201 and S202. Forexample, the position of the obstacle relative to the own vehicle isused to calculate the opposite direction of the obstacle to the ownvehicle as the direction in which the blind spot area is set. Then, theprocessing proceeds to step S204.

In step S204, the blind spot area is set. For example, multiple sensingpoints indicating the outer edge of the obstacle are extracted from thesensing points obtained by the imager 22 in step S101 in FIG. 7. Basedon the angle formed by the own vehicle and the extracted sensing points,the blind spot area is set. Then, the processing ends and proceeds tostep S105 in FIG. 7.

In step S105, for the blind spot area set in step S103, an earlydetermination area including the blind spot area and extended from theblind spot area is set. An example of the processing in step S105 isshown in FIG. 9.

In step S301 in FIG. 9, the path of the obstacle is calculated. The pathof the obstacle can be calculate based on, for example, the position,the traveling direction, and the velocity of the obstacle. Then, in stepS302, the path of the own vehicle is calculated. The path of the ownvehicle can be calculated based on, for example, the position, thetraveling direction, and the velocity of the own vehicle. After stepS302, the processing proceeds to step S303.

In step S303, the direction in which the early determination areaextends from the blind spot area is calculated. In other words, thedirection for setting the extension area extending from the blind spotarea is calculated. For example, the crossing position of the obstaclepath calculated in step S301 and the own vehicle path calculated in stepS303 is calculated, and the direction to the crossing position can beset as the extending direction of the early determination area. Then,the processing proceeds to step S304.

In step S304, the relative velocity of the obstacle to the own vehicleis calculated. The relative velocity can be calculated based on, forexample, the sensing information obtained from the radar 21. Then, theprocessing proceeds to step S305.

In step S305, the amount of the extension of the early determinationarea is calculated based on the relative velocity of the obstacle to theown vehicle calculated in step S304. The ECU 30 stores data such as anumerical expression or a database indicating the relationship betweenthe amount of extension and the relative velocity of the obstacle to theown vehicle. The relative velocity calculated in step S304 is applied tothe data such as the numerical expression or the database to calculatethe amount of the extension of the early determination area. Then, theprocessing ends and proceeds to step S106 in FIG. 7.

In step S106, it is determined whether a moving body is found within theearly determination area set in step S105 for the object sensed in stepS101. If the moving body is found within the early determination area,the processing proceeds to step S107, in which an early determinationflag is set to the moving body within the early determination area.Then, the processing further proceeds to step S108. If no moving body isfound within the early determination area, the processing proceeds fromstep S106 to step S108, with no early determination flag set.

In step S108, it is determined whether there is a collision possibilitythat the object sensed in step S101 and the own vehicle may collide witheach other (collision possibility determination). For example, if thedistance between the path estimated for the object sensed in step S101and the path estimated for the own vehicle is less than a predetermineddistance, and the paths are in contact or close to each other, then thepresence of the collision possibility is determined, and the processingproceeds to step S109. If the distance between the object path and theown vehicle path is equal to or more than the predetermined distance,and the paths are apart from each other, then the absence of thecollision possibility is determined, and the processing is ended.

In step S109, it is determined whether to activate the alarm 41 and thebrake 42 for the object around the own vehicle determined to have acollision possibility in step S108 (activation determination). It isdetermined whether to brake automatically or warn. Specifically, thetime to collision TTC between the object and the own vehicle iscalculated. For example, the TTC is calculated by dividing the directdistance from the current position of the own vehicle to the object bythe relative velocity of the object to the own vehicle. Then, it isdetermined whether the calculated TTC is equal to or less than athreshold TH1 indicating the activation timing. If the TTC is equal toor less than the threshold TH1 (TTC≤TH1), the processing proceeds tostep S110. If the TTC is more than the threshold TH1 (TTC>TH1), theprocessing is ended. Note that the activation timing for the alarm 41 isset at a value more than the activation timing for the brake 42.

For the object with the early determination flag set in step S107, theprocessing in step S108 and step S109 is accelerated compared with anobject with no early determination flag set. In the processing in stepS108 and step S109, the object with no early determination flag set isgiven a normal collision determination period, and the object with theearly determination flag set is given a collision determination periodshorter than the normal period.

In step S110, a command to automatically brake is output to the brake42, while a command to warn is output to the alarm 41. Then, theprocessing is ended.

In the ECU 30 according to the first embodiment, the early determinationarea setting section 34 sets an early determination area, and for anobject sensed within the early determination area, the collisiondetermination section 35 shortens the collision determination periodcompared with the normal period. This enables acceleration of thecollision determination between the own vehicle and an object appearingfrom the blind spot area.

Furthermore, the ECU 30 accelerates the collision determination as to asensed object to enable appropriate avoidance of a collision with amoving body emerging from the blind spot area, thus eliminating the needfor changing the sensing range of the object sensing devices such as theradar 21 and the imager 22. The use of a driving assistance deviceaccording to the ECU 30 for a vehicle incorporating existing objectsensing devices enables more appropriate avoidance of a collision with amoving body emerging from the blind spot area. Note that the techniqueaccording to the ECU 30 may be combined with a technique for allowingthe object sensing devices to more quickly sense a moving body emergingfrom the blind spot area.

Second Embodiment

In a second embodiment, another example of the driving assistancecontrol performed by the ECU 30 described in the first embodiment willnow be described with reference to a flowchart shown in FIG. 10. Theprocess shown in FIG. 10 is repeated at fixed intervals during theoperation of the own vehicle.

The flowchart shown in FIG. 10 differs from the process shown in FIG. 7in including the further processing of step S404. The processing ofsteps S401 to S403, and steps S405 to S410 is the same as the processingof steps S101 to S103, and steps S105 to S110, and will not bedescribed.

In FIG. 10, a blind spot area is set in step S403, and then theprocessing proceeds to step S404. In step S404, it is determined whetherthe blind spot area set in step S403 includes space for any moving body.If it is determined that such a space may be included, the processingproceeds to step S405, and the subsequent steps are performed in thesame manner as in the first embodiment. In step S404, if it isdetermined that no such space is present, the processing proceeds tostep S408 without the execution of the processing of steps S405 to S407.

In step S404, the possibility of the presence of space can be determinedbased on road information around the obstacle. For example, if thedistance between the obstacle and the road edge of the traffic lane nextto the obstacle is equal to or more than a predetermined road edgedistance threshold, the blind spot area is estimated to include enoughspace, and it is determined that there is a possibility of presence. Incontrast, if the distance between the obstacle and the road edge of thetraffic lane next to the obstacle is less than the predetermined roadedge distance threshold, the blind spot area is estimated to include notenough space, and it is determined that there is no possibility ofpresence.

The ECU 30 according to the second embodiment sets an earlydetermination area when the affirmative determination result is providedin the determination of the possibility of presence in step S404, thatis, when the blind spot area is determined to include space for anyobject other than the obstacle. The ECU 30 can thus avoid unnecessarilysetting an early determination area when the blind spot area includes nomoving body, and also avoid unnecessary computation.

Modifications

The driving assistance control process shown in FIG. 10 may furtherinclude the processing of setting an early determination areairrespective of the determination result of the possibility of presencein step S404 if a predetermined cancellation condition is satisfied.Examples of cancellation conditions include the own vehicle entering anintersection and about to turn right or left.

For example, if it is determined that there is no possibility ofpresence in step S404, processing is further performed to determinewhether a predetermined cancellation condition is satisfied(cancellation condition determination processing). If a cancellationcondition is determined to be satisfied, the processing proceeds to stepS405. If no cancellation condition is determined to be satisfied, theprocessing proceeds to step S408.

The cancellation condition determination processing may be performedbefore step S404. For example, the cancellation condition determinationprocessing may be performed immediately before step S404. In this case,if the cancellation condition determination processing provides theaffirmative determination result (if a cancellation condition isdetermined to be satisfied), the processing may skip step S404 andproceed to step S405. If the negative determination result is provided,the processing may proceed to step S404.

The above embodiments enable the following advantageous effects to beachieved.

The ECU 30 functions as a driving assistance device that, based ondetermination as to whether the own vehicle 50 will collide with anobject being around the own vehicle 50 and detected by the objectdetectors such as the radar 21 and the imager 22, that is, based oncollision determination, performs collision avoidance control foravoidance of a collision between the own vehicle 50 and the object. TheECU 30 includes the object sensing section 32, the blind spot areasetting section 33, the early determination area setting section 34, andthe collision determination section 35. The object sensing section 32senses an object around the own vehicle 50. The blind spot area settingsection 33 sets the blind spot area 60, 63 to 66 at an area positionedin the blind spot of the own vehicle 50 blocked by the obstacle sensedby the object sensing section 32 (the other vehicle 51, 53 to 55). Theearly determination area setting section 34 sets the early determinationarea 70 to 73, 75, 76 including the blind spot area 60, 63 to 66 andextended from the blind spot area 60, 63 to 66. The collisiondetermination section 35 accelerates the collision determination for anobject sensed within the early determination area 70 to 73, 75, 76,compared with the collision determination for an object sensed outsidethe early determination area 70 to 73, 75, 76.

In the ECU 30, the early determination area setting section 34 sets theearly determination area 70 to 73, 75, 76, and the collisiondetermination section 35 accelerates the collision determination for anobject sensed within the early determination area 70 to 73, 75, 76, thusenabling acceleration of the collision determination between the ownvehicle 50 and an object appearing from the blind spot area 60, 63 to66.

The ECU 30 accelerates the collision determination between the ownvehicle 50 and an object appearing from the blind spot area 60, 63 to 66(for example, the other vehicle 52 or the pedestrian 56), thuseliminating the need for changing the sensing range of the objectsensing devices such as the radar 21 and the imager 22. In contrast, theECU 30 may be configured to allow control for narrowing down the sensingrange of the object sensing devices in combination with the abovetechnique. For example, control may be performed for narrowing down thesensing range of the object sensing devices to within the earlydetermination area.

The blind spot area setting section 33 may be configured to, forexample, set a blind spot area beyond an obstacle (for example, theother vehicle 51, 53 to 55) from the own vehicle 50. Alternatively, theblind spot area setting section 33 may be configured to set a blind spotarea based on the angle formed by the own vehicle 50 and the sensingpoints 51L and 51R indicating the outer edge of an obstacle.Alternatively, the blind spot area setting section 33 may be configuredto set, within an area positioned in the blind spot of the vehicle, theblind spot area 60, 63 defined by a line 60L, 63N substantially parallelto the orientation or the traveling direction of the obstacle.

The early determination area setting section 34 may be configured to setthe early determination area 70 to 73, 75, 76 for the blind spot area60, 63 to 66 set for an obstacle (such as the other vehicle 51) sensedin the traveling direction of the own vehicle 50. For an obstacle sensedin a direction different from the traveling direction of the own vehicle50, the early determination area may not be set. Even if a moving bodyemerges from the blind spot area of such an obstacle, the collisionavoidance control will often be executable enough without acceleratingthe collision determination.

The early determination area setting section 34 may be configured to setan early determination area extended in a direction in which thepossibility of a collision with the own vehicle 50 is high. This canreduce the computational load in the collision determination within theearly determination area to accelerate the collision determinationfurther.

For example, the early determination area setting section 34 may beconfigured to set the early determination area 71 obtained by extendingthe blind spot area 60 toward the position at which the path 50P of theown vehicle 50 estimated based on the traveling state of the own vehicle50 and the path 51P of the obstacle (the other vehicle 51) estimatedbased on the traveling state of the obstacle cross each other.

Alternatively, the early determination area setting section 34 may beconfigured to set the early determination area 72 obtained by extendingthe blind spot area 60 toward the path 50P of the own vehicle 50estimated based on the traveling state of the own vehicle 50.

Alternatively, the early determination area setting section 34 may beconfigured to set the early determination area 70, 73 obtained byextending the blind spot area 60, 63 along the orientation or thetraveling direction of the obstacle (the other vehicle 51, 53).

Alternatively, when the own vehicle 50 moves toward an intersection, theearly determination area setting section 34 may be configured to set theearly determination area 75 obtained by extending the blind spot area 65toward the own vehicle 50.

Alternatively, when the own vehicle 50 moves toward an intersection, theearly determination area setting section 34 may be configured to set theearly determination area 76 obtained by extending the blind spot area 66along the path 50P of the own vehicle 50 estimated based on thetraveling state of the own vehicle 50.

The early determination area setting section 34 may set the size of theearly determination area 70 to 73, 75, 76 as a fixed value.Alternatively, the early determination area setting section 34 may beconfigured to determine the size of the early determination area 70 to73, 75, 76 based on at least one of the velocity of the obstacle (suchas the other vehicle 51) and the relative velocity of the obstacle tothe own vehicle 50.

The early determination area setting section 34 may be configured to setan early determination area when the blind spot area 60, 63 to 66 isdetermined to include space for any object (for example, the othervehicle 52 or the pedestrian 56) other than the obstacle (such as theother vehicle 51).

When the own vehicle 50 moves toward an intersection, the earlydetermination area setting section 34 may be configured to set the earlydetermination area 70 to 73, 75, 76 irrespective of the result ofdetermination as to whether the blind spot area 60, 63 to 66 includesspace for any object other than the obstacle.

Although the present disclosure has been described based on theembodiments, it is to be understood that the present disclosure is notlimited to the embodiments and configurations. The present disclosureencompasses various modifications and alterations falling within therange of equivalence. Additionally, various combinations and forms aswell as other combinations and forms with one, more than one, or lessthan one element added thereto also fall within the scope and spirit ofthe present disclosure.

The present disclosure provides a driving assistance device (30) forperforming collision avoidance control for avoidance of a collisionbetween an own vehicle (50) and an object being around the own vehicleand detected by an object detector (21, 22), the collision avoidancecontrol being performed based on collision determination as to acollision between the own vehicle and the object. The driving assistancedevice includes: an object sensing section (32) configured to sense anobject around the own vehicle; a blind spot area setting section (33)configured to set a blind spot area (60, 63 to 66) at an area positionedin an own vehicle's blind spot blocked by an obstacle (51, 53 to 55),which is a moving body, sensed by the object sensing section; an earlydetermination area setting section (34) configured to set an earlydetermination area (70 to 73, 75, 76) including the blind spot area andextended from the blind spot area along a path of the obstacle estimatedbased on a traveling direction of the obstacle or a traveling state ofthe obstacle; and a collision determination section (35) configured toaccelerate the collision determination for an object sensed in the earlydetermination area, compared with the collision determination for anobject sensed outside the early determination area.

In the driving assistance device according to the present disclosure,the early determination area setting section sets an early determinationarea including the blind spot area and extended from the blind spotarea. Then, the collision determination for an object sensed in theearly determination area is accelerated compared with the collisiondetermination for an object sensed outside the early determination area.The processing in the driving assistance device accelerates thecollision determination for an object sensed in the early determinationarea, enabling acceleration of the collision determination between theown vehicle and an object appearing from the blind spot area, and alsomore appropriate avoidance of a collision between the own vehicle and anobject emerging from the blind spot area.

What is claimed is:
 1. A driving assistance device for performingcollision avoidance control for avoidance of a collision between an ownvehicle and an object being around the own vehicle and detected by anobject detector, the collision avoidance control being performed basedon collision determination as to a collision between the own vehicle andthe object, the driving assistance device comprising: an object sensingsection configured to sense an object around the own vehicle; a blindspot area setting section configured to set a blind spot area at an areapositioned in an own vehicle's blind spot blocked by an obstacle, whichis a moving body, sensed by the object sensing section; an earlydetermination area setting section configured to set an earlydetermination area including the blind spot area and extended from theblind spot area along a path of the obstacle estimated based on atraveling direction of the obstacle or a traveling state of theobstacle; and a collision determination section configured to acceleratethe collision determination for an object sensed in the earlydetermination area, compared with the collision determination for anobject sensed outside the early determination area.
 2. The drivingassistance device according to claim 1, wherein the early determinationarea setting section sets the early determination area for the blindspot area set for the obstacle sensed in a traveling direction of theown vehicle.
 3. The driving assistance device according to claim 1,wherein the blind spot area setting section sets the blind spot areabeyond the obstacle from the own vehicle.
 4. The driving assistancedevice according to claim 1, wherein the blind spot area setting sectionsets the blind spot area based on an angle formed by the own vehicle andsensing points indicating an outer edge of the obstacle.
 5. The drivingassistance device according to claim 1, wherein the blind spot areasetting section sets, within the area positioned in the own vehicle'sblind spot, the blind spot area defined by a line substantially parallelto an orientation or the traveling direction of the obstacle.
 6. Thedriving assistance device according to claim 1, wherein the earlydetermination area setting section sets the early determination areaobtained by extending the blind spot area toward a position at which apath of the own vehicle estimated based on a traveling state of the ownvehicle and a path of the obstacle estimated based on the travelingstate of the obstacle cross each other.
 7. The driving assistance deviceaccording to claim 1, wherein the early determination area settingsection sets the early determination area obtained by extending theblind spot area toward a path of the own vehicle estimated based on atraveling state of the own vehicle.
 8. The driving assistance deviceaccording to claim 1, wherein when the own vehicle moves toward anintersection, the early determination area setting section sets theearly determination area obtained by extending the blind spot areatoward the own vehicle.
 9. The driving assistance device according toclaim 1, wherein when the own vehicle moves toward an intersection, theearly determination area setting section sets the early determinationarea obtained by extending the blind spot area along a path of the ownvehicle estimated based on a traveling state of the own vehicle.
 10. Thedriving assistance device according to claim 1, wherein the earlydetermination area setting section determines a size of the earlydetermination area based on at least one of a velocity of the obstacleand a relative velocity of the obstacle to the own vehicle.
 11. Thedriving assistance device according to claim 1, wherein the earlydetermination area setting section sets the early determination areawhen the blind spot area is determined to include space for any objectother than the obstacle.
 12. The driving assistance device according toclaim 11, wherein when the own vehicle moves toward an intersection, theearly determination area setting section sets the early determinationarea irrespective of a result of determination as to whether the blindspot area includes space for any object other than the obstacle.
 13. Adriving assistance device for performing collision avoidance control foravoidance of a collision between an own vehicle and an object beingaround the own vehicle and detected by an object detector, the collisionavoidance control being performed based on collision determination as toa collision between the own vehicle and the object, the drivingassistance device comprising: an object sensing section configured tosense an object around the own vehicle; a blind spot area settingsection configured to set a blind spot area at an area positioned in anown vehicle's blind spot blocked by an obstacle sensed by the objectsensing section; an early determination area setting section configuredto set an early determination area including the blind spot area andextended from the blind spot area; and a collision determination sectionconfigured to accelerate the collision determination for an objectsensed in the early determination area, compared with the collisiondetermination for an object sensed outside the early determination area,wherein the early determination area setting section sets the earlydetermination area when the blind spot area is determined to includespace for any object other than the obstacle.
 14. The driving assistancedevice according to claim 13, wherein when the own vehicle moves towardan intersection, the early determination area setting section sets theearly determination area irrespective of a result of determination as towhether the blind spot area includes space for any object other than theobstacle.